The invention relates to a grid floor for a cattle stable comprising a number of mutually parallel supported girders with interspaces.
Usually situated under such a grid floor used in cattle stables is a manure cellar in which the (liquid) manure sinking through the grid floor is collected.
A significant environmental problem associated with cattle farming is the emission of ammonia from the manure. The invention now has for its object to provide a grid floor which contributes to easing of this problem.
In the grid floor according to the invention as characterized in claim 1 the receiving surface closes off toward the top the free surface of the manure in the manure cellar so that the direct ammonia emission out of the manure cellar is greatly restricted. The transporting means remove the (liquid) manure that has fallen through the grid onto the receiving surface via the passage opening to the manure cellar. Because the receiving surface takes a smooth form no or only very little (liquid) manure remains behind on the receiving surface so that no or little ammonia emission occurs herefrom.
A favourable embodiment is characterized in claim 2. The (liquid) manure lying on the receiving surface is urged by the scraper sideways to the gap. The transporting means can hereby be of relatively simple construction.
In order to enable prefabrication of the grid floor according to the invention and rapid installation thereof in a cattle stable, the step of claim 3 is preferably applied.
The application of the step of claim 4 achieves the effect that the liquid manure flows away directly over the receiving surface to the manure cellar.
According to a further development of the invention, the step of claim 5 is applied. The (liquid) manure hereby drips from the drip edges so that only the top surface and the drip edges function as an ammonia-emitting surface. The remaining part of the T-profile remains clean. The total ammonia-emitting surface of the grid itself is hereby limited so that the ammonia emission of the floor is likewise limited.
With the grid floor according to the invention, the ammonia-emitting surface is thus greatly reduced. As is known, roughly half the ammonia released in a cattle stable with a conventional grid floor comes from the grid floor and the other half from the manure cellar. By now according to the invention greatly limiting the emitting surface of the grid floor and the manure cellar, the ammonia emission from the cattle stable is likewise greatly limited.
The girders of the grid floor according to the invention can take a comparatively narrow form due to their T-profile. In preference, the T-profiles are so dimensioned as stated in claim 6. The percentage of open surface of the grid floor is hereby enlarged so that the emitting surface of the grid floor decreases proportionally. The bending stiffness of the girders is partly determined by the height of the body of the T-profile and this body can be made extra high to achieve the desired bending stiffness. The surface of the body remains clean and does not therefore contribute to the ammonia emission. With a narrowing of the flange and a raising of the height of the leg of the T-profile, a reduction is thus achieved in the effective emitting surface.
In stables for calves or pigs the flange can even be as wide as the interspaces between adjacent girders.
In order to obtain a comfortable surface for the cattle, the step of claim 7 is preferably applied. A favourable embodiment is herein characterized in claim 8. The sloping upper surface moreover enables the (liquid) manure falling onto the upper surface to be drained as quickly as possible sideways to the manure cellar.
The T-profiles for the grid floor according to the invention can be special hot or cold-rolled profiles with integrated drip edges. According to a further favourable development of the invention however, the T-profiles can also be commercially available steel profiles which are then provided with separate drip edges. A favourable embodiment is herein characterized in claim 10. The cap can then simultaneously have the suitable grip-providing surface.
With the favourable embodiment as characterized in claim 10, the cap can snap onto the T-profile.
Another favourable embodiment is characterized in claim 11. The reverse U-shaped steel profile is preferably a profile cold-rolled from plate material. This can be dimensioned such that it clamps precisely around the flange of the commercially available steel profile. Further connecting steps are unnecessary.
When therein the step of claim 12 is applied, a grid floor according to the invention is obtained with a long lifespan. Only the outer surface of the cap is herein exposed to the effect of (liquid) manure. The steel T-profile itself remains wholly free of contact with (liquid) manure.
According to a suitable further development, the step of claim 13 is applied.
A further favourable development of the invention is characterized in claim 14. The flexible strips form flaps which can allow (liquid) manure to pass downward but which spring back after this passage into a substantially closed situation, whereby the emission of ammonia from the manure cellar is at least greatly limited. Because the strips are arranged under the flanges, for instance against the leg of the T-profile, they can have a substantial width so that they have an adequate flexibility.
When in addition to or instead thereof the step of claim 15 is applied the manure cellar is moreover wholly closed by the flexible strips so that the emission from the cellar is further limited.
In preference the step of claim 16 is applied herein. The non-stick material ensures that no manure or liquid manure adheres to the surface of the strips so that these do not contribute to the effective emitting surface.
A suitable material is therein characterized in claim 17.
A further favorable embodiment is characterized in claim 18. The separate fingers provide the strips with a very good flexibility so that with certainty they can deflect sufficiently to allow through the (liquid) manure.
The invention will be further elucidated in the following description with reference to the embodiments shown in the figures.